os_q.c

基于51单片机来实现UCOS用一个串口来看到实现阶段

#ifndef  OS_MASTER_FILE
#include "includes.h"
#endif

//队列结构
#if OS_Q_EN && (OS_MAX_QS >= 2)
typedef struct os_q {                  /* QUEUE CONTROL BLOCK                                          */
    struct os_q   *OSQPtr;             /* Link to next queue control block in list of free blocks      */
    void         **OSQStart;           /* Pointer to start of queue data                               */
    void         **OSQEnd;             /* Pointer to end   of queue data                               */
    void         **OSQIn;              /* Pointer to where next message will be inserted  in   the Q   */
    void         **OSQOut;             /* Pointer to where next message will be extracted from the Q   */
    INT16U         OSQSize;            /* Size of queue (maximum number of entries)                    */
    INT16U         OSQEntries;         /* Current number of entries in the queue                       */
} OS_Q;

static  OS_Q        *OSQFreeList;              /* Pointer to list of free QUEUE control blocks         */
static  OS_Q         OSQTbl[OS_MAX_QS];        /* Table of QUEUE control blocks                        */

//无等待地从一个消息队列中取得消息
#if OS_Q_Accept_EN
void *OSQAccept (OS_EVENT *pevent)reentrant
{
    void  *msg;
    OS_Q  *pq;


    OS_ENTER_CRITICAL();
    if (pevent->OSEventType != OS_EVENT_TYPE_Q) {     /* Validate event block type                     */
        OS_EXIT_CRITICAL();
        return ((void *)0);
    }
    pq = pevent->OSEventPtr;                     /* Point at queue control block                       */
    if (pq->OSQEntries != 0) {                   /* See if any messages in the queue                   */
        msg = *pq->OSQOut++;                     /* Yes, extract oldest message from the queue         */
        pq->OSQEntries--;                        /* Update the number of entries in the queue          */
        if (pq->OSQOut == pq->OSQEnd) {          /* Wrap OUT pointer if we are at the end of the queue */
            pq->OSQOut = pq->OSQStart;
        }
    } else {
        msg = (void *)0;                         /* Queue is empty                                     */
    }
    OS_EXIT_CRITICAL();
    return (msg);                                /* Return message received (or NULL)                  */
}
#endif

//建立一个消息队列
#if OS_Q_Create_EN
OS_EVENT *OSQCreate (void **start, INT16U size)reentrant
{
    OS_EVENT *pevent;
    OS_Q     *pq;


    OS_ENTER_CRITICAL();
    pevent = OSEventFreeList;                    /* Get next free event control block                  */
    if (OSEventFreeList != (OS_EVENT *)0) {      /* See if pool of free ECB pool was empty             */
        OSEventFreeList = (OS_EVENT *)OSEventFreeList->OSEventPtr;
    }
    OS_EXIT_CRITICAL();
    if (pevent != (OS_EVENT *)0) {               /* See if we have an event control block              */
        OS_ENTER_CRITICAL();                     /* Get a free queue control block                     */
        pq = OSQFreeList;
        if (OSQFreeList != (OS_Q *)0) {
            OSQFreeList = OSQFreeList->OSQPtr;
        }
        OS_EXIT_CRITICAL();
        if (pq != (OS_Q *)0) {                   /* See if we were able to get a queue control block   */
            pq->OSQStart        = start;         /* Yes, initialize the queue                          */
            pq->OSQEnd          = &start[size];
            pq->OSQIn           = start;
            pq->OSQOut          = start;
            pq->OSQSize         = size;
            pq->OSQEntries      = 0;
            pevent->OSEventType = OS_EVENT_TYPE_Q;
            pevent->OSEventPtr  = pq;
            OSEventWaitListInit(pevent);
        } else {                                 /* No,  since we couldn't get a queue control block   */
            OS_ENTER_CRITICAL();                 /* Return event control block on error                */
            pevent->OSEventPtr = (void *)OSEventFreeList;
            OSEventFreeList    = pevent;
            OS_EXIT_CRITICAL();
            pevent = (OS_EVENT *)0;
        }
    }
    return (pevent);
}
#endif

//清空一个消息队列
#if OS_Q_Flush_EN
INT8U OSQFlush (OS_EVENT *pevent)reentrant
{
    OS_Q  *pq;
    

    OS_ENTER_CRITICAL();
    if (pevent->OSEventType != OS_EVENT_TYPE_Q) {     /* Validate event block type                     */
        OS_EXIT_CRITICAL();
        return (OS_ERR_EVENT_TYPE);
    }
    pq             = pevent->OSEventPtr;              /* Point to queue storage structure              */
    pq->OSQIn      = pq->OSQStart;
    pq->OSQOut     = pq->OSQStart;
    pq->OSQEntries = 0;
    OS_EXIT_CRITICAL();
    return (OS_NO_ERR);
}
#endif

//队列初始化
void OSQInit (void)reentrant
{
    INT16U i;


    for (i = 0; i < (OS_MAX_QS - 1); i++) {      /* Init. list of free QUEUE control blocks            */
        OSQTbl[i].OSQPtr = &OSQTbl[i+1];
    }
    OSQTbl[OS_MAX_QS - 1].OSQPtr = (OS_Q *)0;
    OSQFreeList                  = &OSQTbl[0];
}

//等待一个消息队列中的消息
#if OS_Q_Pend_EN
void *OSQPend (OS_EVENT *pevent, INT16U timeout, INT8U *err)reentrant
{
    void  *msg=NULL;
    OS_Q  *pq;


    OS_ENTER_CRITICAL();
    if (pevent->OSEventType != OS_EVENT_TYPE_Q) {/* Validate event block type                          */
        OS_EXIT_CRITICAL();
        *err = OS_ERR_EVENT_TYPE;
        return ((void *)0);
    }
    pq = pevent->OSEventPtr;                     /* Point at queue control block                       */
    if (pq->OSQEntries != 0) {                   /* See if any messages in the queue                   */
        msg = *pq->OSQOut++;                     /* Yes, extract oldest message from the queue         */
        pq->OSQEntries--;                        /* Update the number of entries in the queue          */
        if (pq->OSQOut == pq->OSQEnd) {          /* Wrap OUT pointer if we are at the end of the queue */
            pq->OSQOut = pq->OSQStart;
        }
        OS_EXIT_CRITICAL();
        *err = OS_NO_ERR;
    } else if (OSIntNesting > 0) {               /* See if called from ISR ...                         */
        OS_EXIT_CRITICAL();                      /* ... can't PEND from an ISR                         */
        *err = OS_ERR_PEND_ISR;
    } else {
        OSTCBCur->OSTCBStat    |= OS_STAT_Q;     /* Task will have to pend for a message to be posted  */
        OSTCBCur->OSTCBDly      = timeout;       /* Load timeout into TCB                              */
        OSEventTaskWait(pevent);                 /* Suspend task until event or timeout occurs         */
        OS_EXIT_CRITICAL();
        OSSched();                               /* Find next highest priority task ready to run       */
        OS_ENTER_CRITICAL();
        if ((msg = OSTCBCur->OSTCBMsg) != (void *)0) {/* Did we get a message?                         */
            OSTCBCur->OSTCBMsg      = (void *)0;      /* Extract message from TCB (Put there by QPost) */
            OSTCBCur->OSTCBStat     = OS_STAT_RDY;
            OSTCBCur->OSTCBEventPtr = (OS_EVENT *)0;  /* No longer waiting for event                   */
            OS_EXIT_CRITICAL();
            *err                    = OS_NO_ERR;
        } else if (OSTCBCur->OSTCBStat & OS_STAT_Q) { /* Timed out if status indicates pending on Q    */
            OSEventTO(pevent);
            OS_EXIT_CRITICAL();
            msg                     = (void *)0;      /* No message received                           */
            *err                    = OS_TIMEOUT;     /* Indicate a timeout occured                    */
        } else {
            msg = *pq->OSQOut++;                      /* Extract message from queue                    */
            pq->OSQEntries--;                         /* Update the number of entries in the queue     */
            if (pq->OSQOut == pq->OSQEnd) {           /* Wrap OUT pointer if we are at the end of Q    */
                pq->OSQOut = pq->OSQStart;
            }
            OSTCBCur->OSTCBEventPtr = (OS_EVENT *)0;
            OS_EXIT_CRITICAL();
            *err = OS_NO_ERR;
        }
    }                                                 
  return (msg);                                     /* Return message received (or NULL)             */
}
#endif

//向消息队列中发送一个消息（FIFO）
#if OS_Q_Post_EN
INT8U OSQPost (OS_EVENT *pevent, void *msg)reentrant
{
    OS_Q   *pq;

    OS_ENTER_CRITICAL();
    if (pevent->OSEventType != OS_EVENT_TYPE_Q) {     /* Validate event block type                     */
        OS_EXIT_CRITICAL();
        return (OS_ERR_EVENT_TYPE);
    }
    if (pevent->OSEventGrp) {                         /* See if any task pending on queue              */
        OSEventTaskRdy(pevent, msg, OS_STAT_Q);       /* Ready highest priority task waiting on event  */
        OS_EXIT_CRITICAL();
        OSSched();                                    /* Find highest priority task ready to run       */
        return (OS_NO_ERR);
    } else {
        pq = pevent->OSEventPtr;                      /* Point to queue control block                  */
        if (pq->OSQEntries >= pq->OSQSize) {          /* Make sure queue is not full                   */
            OS_EXIT_CRITICAL();
            return (OS_Q_FULL);
        } else {
            *pq->OSQIn++ = msg;                       /* Insert message into queue                     */
            pq->OSQEntries++;                         /* Update the nbr of entries in the queue        */
            if (pq->OSQIn == pq->OSQEnd) {            /* Wrap IN ptr if we are at end of queue         */
                pq->OSQIn = pq->OSQStart;
            }
            OS_EXIT_CRITICAL();
        }
        return (OS_NO_ERR);
    }
}
#endif

//向消息队列中发送一个消息（LIFO）
#if OS_Q_PostFront_EN				
INT8U OSQPostFront (OS_EVENT *pevent, void *msg)reentrant
{
    OS_Q   *pq;


    OS_ENTER_CRITICAL();
    if (pevent->OSEventType != OS_EVENT_TYPE_Q) {     /* Validate event block type                     */
        OS_EXIT_CRITICAL();
        return (OS_ERR_EVENT_TYPE);
    }
    if (pevent->OSEventGrp) {                         /* See if any task pending on queue              */
        OSEventTaskRdy(pevent, msg, OS_STAT_Q);       /* Ready highest priority task waiting on event  */
        OS_EXIT_CRITICAL();
        OSSched();                                    /* Find highest priority task ready to run       */
        return (OS_NO_ERR);
    } else {
        pq = pevent->OSEventPtr;                      /* Point to queue control block                  */
        if (pq->OSQEntries >= pq->OSQSize) {          /* Make sure queue is not full                   */
            OS_EXIT_CRITICAL();
            return (OS_Q_FULL);
        } else {
            if (pq->OSQOut == pq->OSQStart) {         /* Wrap OUT ptr if we are at the 1st queue entry */
                pq->OSQOut = pq->OSQEnd;
            }
            pq->OSQOut--;
            *pq->OSQOut = msg;                        /* Insert message into queue                     */
            pq->OSQEntries++;                         /* Update the nbr of entries in the queue        */
            OS_EXIT_CRITICAL();
        }
        return (OS_NO_ERR);
    }
}
#endif

//查询一个消息队列状态
#if OS_Q_Query_EN
INT8U OSQQuery (OS_EVENT *pevent, OS_Q_DATA *dataptr)reentrant
{
    OS_Q   *pq;
    INT8U   i;
    INT8U  *psrc;
    INT8U  *pdest;
    
    
    OS_ENTER_CRITICAL();
    if (pevent->OSEventType != OS_EVENT_TYPE_Q) {          /* Validate event block type                */
        OS_EXIT_CRITICAL();
        return (OS_ERR_EVENT_TYPE);
    }
    dataptr->OSEventGrp = pevent->OSEventGrp;                /* Copy message mailbox wait list           */
    psrc              = &pevent->OSEventTbl[0];
    pdest             = &dataptr->OSEventTbl[0];
    for (i = 0; i < OS_EVENT_TBL_SIZE; i++) {
        *pdest++ = *psrc++;   
    }
    pq = (OS_Q *)pevent->OSEventPtr;
    if (pq->OSQEntries > 0) {
        dataptr->OSMsg = pq->OSQOut;                         /* Get next message to return if available  */
    } else {
        dataptr->OSMsg = (void *)0;
    }
    dataptr->OSNMsgs = pq->OSQEntries;
    dataptr->OSQSize = pq->OSQSize;
    OS_EXIT_CRITICAL();
    return (OS_NO_ERR);
}
#endif
#endif